(a) Technical Field
The present invention relates to a method and apparatus for making a dye-sensitized solar cell (DSSC).
(b) Background Art
One of the most promising new energy sources is solar energy. A silicon type solar cell has been proposed, but it requires high manufacturing cost and shows low economic efficiency. A DSSC has been proposed as an alternative, which requires low production cost while showing energy conversion efficiency comparable to such a silicon solar cell.
In general, the DSSC includes a semiconductor electrode (hereinafter “transparent electrode”), a counter electrode (hereinafter “opposite electrode”) opposite to the transparent electrode, and an electrolyte layer formed between the two electrodes. The transparent electrode includes a transparent conductive substrate in which a transparent substrate is coated with a transparent electrical conductive film. The transparent conductive substrate is coated with porous oxide nanoparticles onto which photosensitive dye molecules are adsorbed. The dye molecules serve to collect solar light and create electron-hole pairs. The opposite electrode includes a transparent conductive substrate in which a transparent substrate is coated with a transparent electrical conductive film. The transparent conductive substrate is coated with platinum or carbon.
Typically, such a DSSC is manufactured as follows. A transparent electrode and an opposite electrode are provided. They are then laminated and bonded so as to allow a predetermined interval to be maintained therebetween. An electrolyte layer is then filled in a space defined between the two electrodes. Thereafter, the bonded electrodes are hermetically sealed.
According to a conventional method, the transparent electrode is prepared by the following method. That is, porous oxide (for example, TiO2) nanoparticles are coated on a transparent conductive substrate. The coated substrate is immersed and fixed in a dye solution in which photosensitive dye molecules are dissolved. Then, the substrate is washed and dried.
The conventional method, however, entails problems. For example, since the transparent conductive substrate coated with porous oxide nanoparticles thereon is soaked and fixed in the dye solution, followed by washing/drying, the process is complicated and takes a long time to be completed. In addition, since the entire substrate has to be immersed in the dye solution, a considerable amount of dye solution more than necessary is used, which results in a waste of materials and requires a larger equipment (solution tank). Further, the adsorbed dye molecules may be separated from the substrate by a shock or a scratch in the middle of manipulating the transparent electrode to laminate the transparent electrode and the opposite electrode. Moreover, in the process of bonding the transparent electrode and the opposite electrode, it is necessary to perform a high-temperature treatment, which may decompose the dye molecules.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.